1. FIELD OF THE INVENTION
The present invention relates to a sanitary tampon which is inserted into a body cavity such as a woman""s vagina to absorb menstrual fluid, blood and other kinds of body fluid.
2. DESCRIPTION OF THE RELATED ART
Recently, various types of sanitary tampons have been developed and put on the market. For example, Japanese Unexamined Patent Publication (Kokai) No. Heisei 1-146548 discloses a sanitary tampon that comprises an absorbent of hydrophilic fibers and an outer layer of a hydrophobic sheet mixed with hydrophilic fibers. Japanese Unexamined Patent Publication (Kokai) No. Heisei 3-146058 discloses a tampon that comprises a columnar, highly-compressed core and an outer envelope. Japanese Unexamined Patent Publication (Kokai) No. Heisei 5-68695 discloses a tampon which comprises a combination of sheets having a higher fiber density and sheets having a lower fiber density and is so constructed that, when formed into a columnar structure, the sheets having a lower fiber density are partly exposed outside the surface of the structure. These tampons have columnar structures of compressed absorbent fiber materials. While used, they absorb menstrual discharges, and are then uncompressed. As a result, the thus-uncompressed tampons expand to block the vaginal cavity, and can further absorb the menstrual discharges.
However, since these types of the tampons have such columnar structures formed by highly compressing integrated fibrous mats, they are problematic in that the fibrous mats constituting them are too rigid and are therefore hardly restored to their original, non-compressed size so as to well fit into the vagina, and that the menstrual discharges often leak outside through the inevitable space between an inner wall of the vagina and the tampon.
On the other hand, Japanese Unexamined Patent Publication (Kokai) No. Showa 62-236547 discloses a tampon comprising a plurality of small fiber agglomerations. In this tampon, the constituent fiber agglomerations have some space between them. Therefore, the tampon could be easily deformed, and could well fit into the vagina. However, since the fiber agglomerations constituting the tampon have some space between them, the fiber content of the tampon will reduce if the density of the fiber agglomerations is lowered so as to increase the absorption rate into the fiber agglomerations. If so, the absorbability of the tampon as a whole is thereby reduced. On the other hand, if the density of the fiber agglomerations is increased so as to increase the absorbability of the tampon, the absorption rate into the fiber agglomerations will lower. In addition, since the fiber agglomerations constituting the tampon have some space between them, the tampon itself is not rigid enough to easily insert the tampon into the vagina.
An object of the present invention is to provide a tampon which has high absorbability, and hardly forms a space between the tampon and an inner wall of the vagina.
According to one aspect of the invention, a sanitary tampon may comprise an absorbent wrapped by a liquid-pervious sheet, wherein;
the absorbent is a mass of a plurality of compressed, small fiber agglomerations, at least the small fiber agglomerations located in the peripheral region of the absorbent are bonded to each other via hydrogen bonding therebetween.
The absorbent of the sanitary tampon of the invention is formed of a plurality of small fiber agglomerations bonded to each other. When the tampon has been inserted into the vagina and brought into contact with a small quantity of discharges therein, the hydrogen bonding between the small fiber agglomerations constituting the absorbent is broken and, as a result, the thus-broken fiber agglomerations exhibit their individual behavior. In that condition, the compressed fiber agglomerations are restored to their original, non-compressed size. Accordingly, the tampon in the vagina well fits to the inner wall of the vagina with no space between the tampon and the inner wall of the vagina. In addition, since the small fiber agglomerations constituting the absorbent of the tampon are tightly compressed and since at least the small fiber agglomerations located in the peripheral region of the absorbent are bonded to each other via hydrogen bonding therebetween, the tampon is rigid by itself and is easy to insert into the vagina.
The density of the small fiber agglomerations located in the center region of the absorbent of the tampon may be higher than that of the small fiber agglomerations located in the peripheral region thereof. In the tampon of this embodiment, since the density of the small fiber agglomerations located in the peripheral region of the absorbent is lower than that of the others, the small fiber agglomerations located in the peripheral region can rapidly absorb discharges to break the hydrogen bonding between them, whereby the absorbent shall have a freedom of behavior as a whole. As a result, the small fiber agglomerations having a higher density and located in the center region of the absorbent can behave relatively freely. The small fiber agglomeration having a higher density can expand to a higher degree when having absorbed discharges, and, as a result, the absorbent well expands to facilitate fitting in the vagina.
The small fiber agglomerations located in the center region of the absorbent may be formed of noncellulosic fibers alone or of a combination of cellulosic fibers and noncellulosic fibers, and those located in the peripheral region thereof may be formed of cellulosic fibers alone or of a combination of cellulosic fibers and noncellulosic fibers; and the small fiber agglomerations located in the center region of the absorbent may contain a larger quantity of noncellulosic fibers than those located in the peripheral region thereof. In such a tampon, the small fiber agglomerations located in the center region of the absorbent are essentially formed of noncellulosic fibers. Therefore, the elastic recovery of this tampon is high. When the small fiber agglomerations essentially formed of cellulosic fibers in the peripheral region of the absorbent of the tampon have absorbed discharges to break the hydrogen bonding between them, the absorbent is rapidly expanded owing to the expansion force of the small fiber agglomerations located in the center region of the absorbent.
If desired, the respective small fiber agglomerations may be of a core/shell structure, and the density of the core of each fiber agglomeration is higher than that of the shell.
Also if desired, the core of the small fiber agglomeration is formed of noncellulosic fibers alone or of a combination of cellulosic fibers and noncellulosic fibers; and the shell thereof is formed of cellulosic fibers alone or of a combination of cellulosic fibers and noncellulosic fibers, and the core contains a larger quantity of noncellulosic fibers than the shell.
Preferably, in the tampon of the invention; the small fiber agglomerations constituting the absorbent may contain both cellulosic fibers and noncellulosic fibers in a blend ratio of cellulosic fibers to noncellulosic fibers falling between 0.5:1 and 4:1.
Also preferably, the mean fiber density of the absorbent falls between 0.2 and 0.9 g/cm3.
According to another aspect of the invention, a sanitary tampon-may comprise an absorbent wrapped by a liquid-pervious sheet, wherein;
the absorbent includes a web of compressed and hydrogen-bonded fibers; and a plurality of small fiber agglomerations contained in the web, and the small fiber agglomerations are compressed to have a higher density than the web.
According to still another aspect of the invention, a sanitary tampon may comprise an absorbent wrapped by a liquid-pervious sheet, wherein;
the absorbent includes a web of compressed and hydrogen-bonded cellulosic fibers alone or of a combination of cellulosic fibers and noncellulosic fibers all compressed and hydrogen-bonded; and a plurality of small fiber agglomerations of noncellulosic fibers alone or of a combination of cellulosic fibers and noncellulosic fibers to be contained in the web, and the noncellulosic fiber content of the small fiber agglomerations is higher than that of the web.
In these tampons of the invention, the fibrous web rapidly absorbs discharges to break the hydrogen bonding of the fibers constituting it, whereby the absorbent gets a freedom of behavior. In that condition, the small fiber agglomerations having a higher density in the fibrous web, or those therein containing noncellulosic fibers and therefore having an increased degree of elastic recovery expand to a great extent, and, as a result, the absorbent well expands to facilitate fitting in the vagina.
In the tampons of the invention, it is desirable that the small fiber agglomerations are formed by winding up fibers. More preferably, the small fiber agglomerations of high-density fibers or those of noncellulosic fibers therein are formed by winding up the fibers, so that their expansion recovery becomes large when they have absorbed discharges.